Variable-resistance material memory structures often rely upon isolation of individual memory cells. The memory cells may be connected to a bit line in a parallel manner, and four metal layers, including the word line, bit line, top-electrode selection line, and the global data bus are used to program and read the data. The isolation of the individual memory cells creates tension for the designer to continue to miniaturize circuitry.
What are needed are methods to form better structures that can address these challenges. What are also needed are improved variable-resistance material random-access memory structures that can also address these challenges.